SACRAMENTO – Lance Armstrong kept his head down on the stationary bike, concentrating on his iPod and his pedaling technique. Each time he glanced up, dozens of fans barricaded 10 feet away snapped pictures and murmured with delight.

Even Armstrong’s warmup exercises for Saturday’s prologue to the Tour of California were a sensation on Sacramento’s downtown streets. Armstrong knows the crowds and attention will only get bigger – albeit probably not friendlier – as he moves toward his attempt to win another Tour de France title.

After kicking off his comeback in Australia last month, Armstrong returned to competitive cycling in his native country with a smooth 10th-place finish in the prologue.

“People are excited, but I don’t think they’re as excited as I am,” Armstrong said. “I’m glad to be here, and appreciate the support.”

The seven-time Tour de France winner finished the 2.4-mile course around California’s Capitol building in 4 minutes, 37.17 seconds, coming in just 4.3 seconds off the pace set moments later by Switzerland’s Fabian Cancellara.

Levi Leipheimer, Armstrong’s Astana teammate and the race’s two-time defending champion, finished second at 4:34.11 in the day’s final ride. Floyd Landis, who’s beginning his comeback from a two-year doping ban, came in 90th amid warm cheers on the next-to-last start.

But Armstrong decidedly was the main attraction to tens of thousands of fans who crowded the downtown Sacramento streets for one fleeting glimpse of his abbreviated ride.

“All in all, I wanted to be top 10, top 15, so I have to be pretty happy,” said Armstrong, whose stated goal in his first Tour of California is to assist Leipheimer to victory. “It’s a new sensation, because I haven’t trained for efforts like that. We changed the time trial position a little bit, so it’s the first time I got to go as hard as I could with a new position.”

After the race, California governor Arnold Schwarzenegger appeared on the Capitol steps with the 37-year-old Armstrong. His comeback from a 3 -year break began at the Tour Down Under, where similarly fascinated crowds cheered him.

Astana’s team trailer was surrounded by hundreds of picture-snapping, autograph-seeking fans who yelled inspirational thoughts and even a few pickup lines. Shorter fans had little chance of seeing Armstrong over the people lined up 10 deep around Astana’s warmup tent.

Armstrong described the mob scene as “amazing.”

Armstrong is a devotee of Twitter, the online message service on which he provides repeated updates on his day-to-day life. He jumped online right after the race with a quick message for his followers: “Done with the prologue. Ouch, that hurt. Thanks to massive crowds here in Sac.”

While Armstrong and Leipheimer emerged from the prologue in ideal position for today’s lengthy Stage 1 from Davis to Santa Rosa, other prominent riders didn’t fare quite as well. Landis, the disgraced 2006 Tour de France champion, finished well back in the pack of the prologue’s 136 competitors, coming in 20.4seconds off the pace.

Cancellara will wear the Tour of California’s first yellow jersey for the second straight year, no surprise for a former world time trial champion.

“It was big on the agenda for us to get this win for the team,” said Cancellara, who rides for Team Saxo Bank. “Now the pressure is gone, and we can see and enjoy the (yellow) jersey.”